[blattimwind]

Smartphones work to some extent because they are relatively light and you hold them in your hand. This means it is very much not a rigid surface. Typing on a projective keyboard on e.g. a desk is very unpleasant, because you are pecking a hard, rigid surface with your fingers.

[setr]

Sure, but at least in my imagination, the primary use-case doesn't care. The primary use-case being that you have a surface, but no/inaccessible laptop/desktop, and you need to type up something long and quickly; perhaps debugging a production problem as a sysadmin, or trying to stop an email chain from going out of control as a PM, or trying to respond a high priority client immediately, during lunch or any other out-of-office reason. Or hell, trying to respond to an HN thread with a long-form comment before the conversation dies out.

I can't trust emails on a smartphones because they're so error-prone. If this thing is reliable in its input, and easy to setup, then the "unpleasantness" of typing on a desk is very low on the list of concerns, unless it's extremely unpleasant, if not outright painful.

And unless you're a hunt-and-pecker (which couldn't feasibly use the tool in the first place, afaict), I don't see how it could be that unpleasant. And playing with the idea on my desk.. it's not the greatest feeling, but its hardly a showstopper.

It's not a general keyboard replacement. It's a few-usecase and higher-constraint keyboard replacement; the only thing that matters is whether it supports those specific fewer usecases significantly better than the currently available alternatives, because it doesn't hinder using the general tool as a fallback.